Technical Reports

Controlled Tank Car Impact Tests

  • 01
  • Aug
  • 1994
AUTHOR: R. K. Larson Jr. and B.R. Rajkumar
SUBJECT: Hazardous Materials
KEYWORDS: tank car impact; safety vent nozzle surge pressures during impact; impact conditions resulting in frangible disk rupture; safety vent nozzle surge pressure reducer devices
ABSTRACT: A series of controlled tank car impact tests were performed by the Association of American Railroads as part of a Federal Railroad Administration Task Order entitled “Hazardous Materials Transportation Safety Research Test Program”. The objective of these tests, in which a weighted locomotive was coupled to a stationary DOT 111A100W2 tank car at different speeds, was to determine the magnitude of surge pressures that the safety vent is exposed to and to test devices that are designed to reduce these surge pressures and prevent the premature rupture of frangible disks. Test results support the following conclusions: (1) when loaded to a shell full condition, a tank car of the design tested will develop safety vent nozzle surge pressures sufficient to rupture 60 and 100 psi frangible discs during impacts that produce coupler forces of 800 kips and 1100 kips, respectively; (2) a large decrease in safety vent nozzle surge pressures results when lading outage is changed from 0% to 1%; (3) for impact speeds between 5 and 7 mph, substantially higher coupler forces were developed for a test car which was loaded to a shell full condition as compared to a 1% outage condition; (4) when installed, two baffle-type safety vent nozzle surge pressure reduces effectively reduced surge pressures acting on frangible discs installed in 2.5 inch and 6.5 inch diameter nozzle safety vents.
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